Mackie E J, Murphy L I
School of Veterinary Science, University of Melbourne, Parkville, Victoria, Australia.
Microsc Res Tech. 1998 Oct 15;43(2):102-10. doi: 10.1002/(SICI)1097-0029(19981015)43:2<102::AID-JEMT3>3.0.CO;2-T.
A number of large multidomain extracellular matrix glycoproteins, including fibronectin and members of the tenascin and thrombospondin families, are expressed in locations that suggest they may be involved in the process of chondrogenesis. During early limb morphogenesis, tenascin-C is selectively associated with condensing chondrogenic mesenchyme. With progressive development of endochondral bones, tenascin-C is absent from the matrix surrounding proliferating and hypertrophic chondrocytes, but remains in a restricted distribution in peripheral epiphyseal cartilage. During long bone development, patterns of expression of tenascin-C splice variants differ between chondrogenic and osteogenic regions, suggesting that different isoforms may have different functional roles. Tenascin-C presented as a substratum for chick wing bud mesenchymal cells induces chondrogenic differentiation. In early studies, fibronectin was found to inhibit chondrogenesis, despite being abundant in early chondrogenic mesenchyme. Recent studies showing differential effects of fibronectin splice variants on prechondrogenic mesenchymal condensation may explain this paradox. Members of the thrombospondin gene family are expressed in chondrogenic tissues at different stages, suggesting that they each play a unique role in cartilage development.
一些大型多结构域细胞外基质糖蛋白，包括纤连蛋白、腱生蛋白家族成员和血小板反应蛋白家族成员，在某些位置表达，这表明它们可能参与软骨形成过程。在肢体早期形态发生过程中，腱生蛋白-C与凝聚的软骨形成间充质选择性相关。随着软骨内骨的逐渐发育，增殖和肥大软骨细胞周围的基质中不存在腱生蛋白-C，但在周围骨骺软骨中仍呈局限性分布。在长骨发育过程中，腱生蛋白-C剪接变体在软骨形成和成骨区域的表达模式不同，这表明不同的异构体可能具有不同的功能作用。作为鸡翼芽间充质细胞基质的腱生蛋白-C可诱导软骨形成分化。在早期研究中，尽管纤连蛋白在早期软骨形成间充质中含量丰富，但却被发现抑制软骨形成。最近的研究表明纤连蛋白剪接变体对软骨形成前间充质凝聚有不同影响，这可能解释了这一矛盾现象。血小板反应蛋白基因家族成员在软骨形成组织的不同阶段表达，这表明它们在软骨发育中各自发挥独特作用。
